This invention refers to an apparatus for releasibly securing a freight car container of standard type (ISO standard) to a platform, such as the flat bed of a truck and the like wherein the locking device can be completely withdrawn beneath the surface of the platform when not in use and that the vertical dimension of the device is shortened when retracted.
As is well known in the art, standard freight containers of the type described, have at each corner fitting in which there is an elongated orifice in the horizontal face, which orifice opens into a recess within the corner fitting. There is a wide variety of devices that have been designed to releasibly lock corner fittings of one container to corner fittings of another container and also to releasibly lock a corner fitting to a deck. The state of the art is shown in U.S. Pat. No. 4,212,251, issued July 15, 1980 to John DiMartino entitled "Key Actuated Stacker Locking Device", which shows a locking device which can be welded to a deck having a base plate, a neck member and a rotatable crosshead member. In this type device, the crosshead member and neck member are brought into alignment with each other as they rise up from the base member, and the corner fitting is loaded onto it with the crosshead member and the neck member entering the horizontal orifice of the corner fitting. Thereafter, the crosshead member is rotated so that its elongated axis biases across the elongated opening of the elongated orifice or the corner fitting and abuts onto the inner wall of the corner fitting to lock it to the deck. The base can be welded onto the deck to cause the container to thereby become affixed releasibly to the deck.
A particular problem arises when locking devices are attempted to be used on flat bed truck platforms and railroad car platforms in that the ideal place to space the locking device is located over the wheel. In such instances, the space between the wheel and the underside of the platform is very narrow and for a retractable device to be successfully employed here; a way has been sought to shorten the vertical dimension of the lock when it is in its retracted position to avoid having the locking device mechanism from contacting the outer surface of the wheel.
The prior art devices have been very useful in ships and railroad flat cars which are designed to merely haul containers. The use of containers on flat bed trucks has been limited due to the fact that when the prior art container locks are welded onto the deck of the truck, they are left protruding up above the deck of the truck to block the use of the full truck bed platform which it is desired to lay flat items such as sheet metal, flush onto the deck. This same problem exists with respect to flatbed railroad cars.
The art has sought methods of lashing the container onto the truck bed; in general the truckers utilize chain lashings to hold the containers onto the deck because of the problem with prior art locking devices sticking up through the deck when not in use. The use of chain lashing is both an inconvenience which is costly in turn around time, in loading and unloading, and further, it is dangerous due to the fact that the chains are not the safest method of securing the container to the deck.
The art has long sought a container interlock which is economic to produce, easily actuable and which can overcome the inconvenience posed by lashing containers to a deck, and which can be retracted beneath the deck when it is so desired, and still have the strength and safety features of conventional interlocks. The interlock for use on such truck body surfaces must be easily installed and easily removed to a point below the deck and be able to withstand tremendous forces applied to them in normal use.